The proposed SCOR program will focus on the etiology and pathophysiology of hyaline membrane disease (HMD), with the ultimate aim of improved treatment and prevention. The investigators have produced a homologue of HMD in the prematurely delivered monkey (M. nemestrina). This model provides a unique opportunity to obtain precise information about sequential pathophysiological and biochemical changes occurring throughout the course and reparitive processes of HMD. Specific projects will focus on sequential changes occurring in the lung, including mechanical properties, gas exchange, quantitative and qualitative estimates of surface-active lipoproteins, and ultrastructure. Other projects related to pathogenesis include studies of synthesis, storage, and turnover of surface active pulmonary lipoproteins in the mutant-beige mouse, and studies on the development of ventilatory control in relation to maturation of the central nervous system in the newborn monkey. Specific treatment and prevention of HMD is lacking and will require increased knowledge of pathogenesis. In the interim, there is need for improvements in supportive therapy. Several projects are directed at improved monitoring (ultrasonic detection of pneumothorax, continuous transcutaneous PO2 electrodes) and treatment (early intervention with distending airway pressure). Long term consequences of HMD and current methods of intervention and treatment will also be examined. An evaluation of survivors of HMD and low birthweight will be conducted by a multidisciplinary child development team to determine the effects on neurological, emotional and mental development.